Need Advice Please

I am making a zombie cake due in 10 days. the zombie part will be the head and shoulders constructed from RKT and covered in fondant. I plan to do this part early to give myself plenty of time in order for it to come out good ( plus the time to redo it if the 1st one fails) I have found recipes for blood using corn syrup and food coloring, my question is will the corn syrup go bad if put on too early?

AIt won't go bad but it will run off and pool and melt fondant becoming a nasty icky red mess.... make your fake blood and store it in a pot then pour it on just before you unveil the cake (or if you are selling this cake give the customer the blood and tell them to apply liberally just before they unveil it).

If you are happy using modelling chocolate/candy clay I'd recommend that- I find it way easier to do faces with as you can keep remodelling it once it's applied whereas fondant dries and cracks, but with only 10 days to go I wouldn't jump into using it for the first time...

Have fun :-) Looking forward to seeing your cake! Would you maybe PM me a pic if it's too scary for the galleries here?? :-D